Water Heater Brochure

SIMPLE TANKLESS SIZING
Tankless Models Ground Water Temperature Factor
The temperature of incoming ground water (cold water inlet temperature) varies greatly throughout the U.S.
and also fluctuates with the changing of the seasons. The temperature of water as it enters the water heater
will determine the amount of “temperature rise” required to achieve the desired hot water outlet temperature
(120°F is recommended).The best way to measure incoming ground water temperature is to use a thermometer
to measure cold water temperature during the coldest season of the year. To simplify the process, use this map to
determine whether your installation location is in the Southern Zone, Central Zone or Northern Zone.
Peak Hot Water Demand
The next step is to determine how many gallons per minute of hot water will be required during the busiest usage
period (peak demand). Consider all appliances and fixtures that use hot water, including lavatory faucets, kitchen
faucets, washing machines, dishwashers, showers and bathtubs. Be sure to determine how many appliances and
fixtures will be used at the same time (peak demand).
Average Ground Water
Temperature: 62°F to 77°F
Average Ground Water
Temperature: 52°F to 61°F
Average Ground Water
Temperature: 37°F to 51°F
NORTHERN ZONESOUTHERN ZONE CENTRAL ZONE
Remember, these are general recommendations. Your A. O. Smith Water Heater Specialist can review your family’s needs in even greater detail to make sure the model you choose
will always provide enough hot water to meet the demand.
AVERAGE GROUND WATER TEMPERATURE
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